Authors: Tianqiang Liu, Michel Thiebaut de Schotten, Irene Altarelli , Franck Ramus, Jingjing Zhao.
Publication: Human Brain Mapping (Wiley). First published online: 09 July 2022 2022 | DOI: 10.1002/hbm.25997
It has been suggested that developmental dyslexia may have two dissociable causes-a phonological deficit and a visual attention span (VAS) deficit. Yet, neural evidence for such a dissociation is still lacking. This study adopted a data-driven approach to white matter network analysis to explore hubs and hub-related networks corresponding to VAS and phonological accuracy in a group of French dyslexic children aged from 9 to 14 years. A double dissociation in brain-behavior relations was observed. Structural connectivity of the occipital-parietal network surrounding the left superior occipital gyrus hub accounted for individual differences in dyslexic children’s VAS, but not in phonological processing accuracy. In contrast, structural connectivity of two networks: the temporal-parietal-occipital network surrounding the left middle temporal gyrus hub and the frontal network surrounding the left medial orbital superior frontal gyrus hub, accounted for individual differences in dyslexic children’s phonological processing accuracy, but not in VAS. Our findings provide evidence in favor of distinct neural circuits corresponding to VAS and phonological deficits in developmental dyslexia. The study points to connectivity-constrained white matter subnetwork dysfunction as a key principle for understanding individual differences of cognitive deficits in developmental dyslexia.
Liu, T., Thiebaut de Schotten, M., Altarelli, I., Ramus, F., & Zhao, J. (2022). Neural dissociation of visual attention span and phonological deficits in developmental dyslexia: A hub-based white matter network analysis. Human brain mapping, 10.1002/hbm.25997. Advance online publication. https://doi.org/10.1002/hbm.25997
One of the main results of the present study was that we observed an independent subnetwork corresponding to VAS but not phonological skills in dyslexic children.
In sum, we provide the first piece of anatomical evidence for a distinct white matter network associated with VAS deficit in dyslexia.